Microelectromechanical systems (MEMS) are used in a variety of situations and applications. MEMS can be very small, such as having lateral dimensions in a range of 0.02 to 1.0 mm, and can be used in many applications including sensing (e.g., pressure sensors, gyroscopes, accelerometers, etc.), actuating, switching and others. Commercial applications of MEMS include ink jet printers, automobile airbag systems, microphones, and others, including displays.
Conventional MEMS used in displays typically comprise moveable conductive membranes that can form individual pixels or arrays in flat-panel displays. The moveable membranes are formed by etching or otherwise removing a sacrificial layer of covered silicon oxide from the structure, thereby forming a cavity and releasing at least a portion of the membrane from the underlying substrate so that the membrane can move and flex in operation. There are several drawbacks associated with this technique and the use of silicon oxide, including: the ability to integrate the MEMS in other systems and manufacturing processes; the achievable quality and selectivity of the etching of the sacrificial layer; and cost and overall complexity.
Other conventional display technologies include use digital light processing (DLP) and liquid crystal on silicon (LCOS). DLP techniques comprise arrays of tiny mirrors that are switched or tilted electrostatically to direct light in different directions. Additional lenses and light absorbers are necessary to remove or contain undesired light and form an image. In LCOS, liquid crystals are applied to silicon chips, though it is difficult to seal the liquid in a cavity between silicon chips and bond them, making these techniques more complicated and expensive.
Thus, there is a need for improved display technologies.